Ammonium Nitrate Explosives for Civil Applications E-Book

Erode G. Mahadevan

• Herausgeber: Wiley-VCH
• Kategorie: Fachliteratur
• Sprache: Englisch

Seitenzahl: 418

Veröffentlichungsjahr: 2013

Beschreibung

The book describes the science and technology of formulation and manufacturing of non-nitroglycerine explosives with ammonium nitrate as the main ingredient. Based on the author's industry experience of more than thirty years, it provides an unparalleled treatment of one of the commercially most important classes of explosives and therefore stimulates further research and development efforts in the field of explosives for civil applications.

Leseprobe

Table of Contents

Related Titles

Title Page

Copyright

Preface

Acknowledgment

Chapter 1: Classification of Explosives

1.1 Initiation Sensitivity

1.2 Size

1.3 Usage

1.4 Physical Form

Chapter 2: Explosive Science

2.1 Introduction

2.2 Initiation and Detonation

2.3 Propagation and Detonation

2.4 Reaction Chemistry in Explosives

References

Chapter 3: Ammonium Nitrate Explosives

3.1 Introduction

3.2 Design of Commercial Explosives

3.3 Tests

3.4 Assessment of Safety and Stability Characteristics

3.5 Summary

References

Chapter 4: Ammonium Nitrate and AN/FO

4.1 Introduction and History

4.2 Physical and Chemical Properties of Ammonium Nitrate

4.3 Manufacture of Ammonium Nitrate

4.4 Ammonium Nitrate Fuel Oil Explosives

References

Further Reading

Chapter 5: Slurries and Water Gels

5.1 Development

5.2 Design

5.3 Process Technology

5.4 Quality Checks

5.5 Process Hazards (Dust Explosions/Fire Hazards/Health Hazards)

5.6 Role of GG

5.7 Permissible Explosives

5.8 General Purpose Small-Diameter Explosives (GPSD)

5.9 Sensitizers

References

Further Reading

Chapter 6: Emulsion Explosives

6.1 Introduction

6.2 Concept of Emulsion Explosives

6.3 General Composition of Emulsion Explosives

6.4 Structure and Rheology

6.5 Composition and Theory of Emulsion Explosives

6.6 Manufacture

6.7 Quality Checks

6.8 Explosive Properties of Emulsion Matrix/Explosives

6.9 Permissible Emulsions

6.10 General Purpose Small-Diameter (GPSD) Emulsion Explosives

6.11 Bulk Emulsions

6.12 Heavy AN/FO

6.13 Packaged Large-Diameter Emulsion Explosives

References

Further Reading

Chapter 7: Research and Development

7.1 Areas of Interest

7.2 Development Work and Upscaling

7.3 Management of R&D

Chapter 8: Functional Safety during Manufacture of AN Explosives

8.1 Introduction – Personal View Point on Safety

8.2 Safety Considerations in AN Explosives

8.3 Explosion Hazards in Equipment

8.4 Concluding Remarks

References

Chapter 9: Economics of AN-Based Explosives

9.1 In Manufacture

9.2 In Applications

9.3 Blast Design

9.4 Influence of Explosives in Underground Mining

References

Chapter 10: Current Status and Concluding Remarks

Appendix A

Appendix B: Guidelines for Investigation of an Accident

B.1 Introduction

B.2 Detailed Inspection

B.3 Interviewing and Questioning

B.4 Collection of Samples

B.5 Examination of Witnesses

B.6 Examination of Dead/Injured

Index

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The Author

Dr. Erode G. Mahadevan

Technology Consultant

C-22 Vikrampuri Colony

Secunderabad 500009

India

All books published by Wiley-VCH are carefully produced. Nevertheless, authors, editors, and publisher do not warrant the information contained in these books, including this book, to be free of errors. Readers are advised to keep in mind that statements, data, illustrations, procedural details or other items may inadvertently be inaccurate.

Library of Congress Card No.: applied for

British Library Cataloguing-in-Publication Data

A catalogue record for this book is available from the British Library.

Bibliographic information published by the Deutsche Nationalbibliothek

The Deutsche Nationalbibliothek lists this publication in the Deutsche Nationalbibliografie; detailed bibliographic data are available on the Internet at <http://dnb.d-nb.de>.

© 2013 Wiley-VCH Verlag & Co. KGaA, Boschstr. 12, 69469 Weinheim, Germany

All rights reserved (including those of translation into other languages). No part of this book may be reproduced in any form — by photoprinting, microfilm, or any other means — nor transmitted or translated into a machine language without written permission from the publishers. Registered names, trademarks, etc. used in this book, even when not specifically marked as such, are not to be considered unprotected by law.

Print ISBN: 978-3-527-33028-7

ePDF ISBN: 978-3-527-64570-1

ePub ISBN: 978-3-527-64569-5

mobi ISBN: 978-3-527-64571-8

oBook ISBN: 978-3-527-64568-8

Preface

Ammonium nitrate (AN) explosives came into prominence in the last three decades (40 years) for civil applications as it provided a greater margin of safety to the manufacturer and end user as compared to the then popular nitroglycerine (NG) explosives. Due to rapid industrialization over the last 30 years, there has been a surge in mining and infrastructure activities which in turn has triggered high demand for civil explosives at all types of remote and tough locations. Mining methodology also underwent a change to cater to these requirements and huge open cast mines which need for their efficient operations large volumes of explosives delivered at mine site are operating in great numbers. Such enhanced requirements could only be satisfied by AN-based civil explosives which can be manufactured in high tonnages with a good margin of safety and low capital investment. Thus in many countries, manufacture and use of NG explosives were reduced drastically or abandoned, and AN explosives were used instead. Rapid development of AN-based explosives for all types of applications including underground gassy coal mines took place between 1970 and 1990 to fill in the void left by NG explosives and a number of patents appeared during this time. Over the years, however, the manufacture in industrial scale has settled down to fairly common practices and raw materials.

Despite the importance of the AN-based civil explosives today, there has not been much written and published about these explosives in detail perhaps because of their unglamorous nature as compared to military explosives and propellants. It is my intention to fill this gap by devoting the contents of this book exclusively to the technology of manufacture of AN civil explosives. This book will deal with three such products – AN/fuel oil explosives (AN/FO), slurry and water gel explosives, and emulsions explosives, in great detail as they comprise nearly 90% of the explosives used worldwide in civil sector.

Much has been published about the chemistry and science of explosives as well as test methods employed to determine their characteristics. It is my intention not to repeat these but mention only the most important aspects applicable to AN explosive under consideration here. On the other hand, the book will concentrate on providing valid data and sensible manufacturing guidelines based on the author's hands-on experience of more than 35 years in this field. There is no attempt here to bring into print any kind of proprietary information and “tricks of the trade” being practiced in the industry. The author hopes that the contents will benefit the persons engaged in the industry to have a better understanding of the role of the critical factors involved in manufacturing good explosives in a safe way. It is also the fond hope of the author that through this book young and fresh minds will get stimulated to take up research in this subject, which has been woefully very meager, and contribute toward better understanding of the basics leading to safer and hopefully cheaper products in keeping with current environmental conditions.

I feel the chapters describing the critical role of raw materials like guar gums, aluminum powders, emulsifiers, processing and packing technology, and optimum utilization of explosives energy in field applications will be of great interest to the reader. Strangely while the science of explosives includes aspects of importance from complex subjects like thermodynamics, colloid chemistry, powder metallurgy, mixing technology, and detonation physics, the commercial manufacture of AN explosives for civil application has reduced to a fairly low technology, high volume industry where know-how is supreme and know-why is of low importance. Hence there is no theoretical and mathematical approach of the subject in the book but attempt is made to demystify and simplify concepts of explosive phenomena so as to enable those performing routine jobs in this industry to understand and appreciate more their occupation, thereby deriving more intellectual satisfaction.

The contents of the book will be of interest to persons engaged in the civil explosives industry in all its aspects such as manufacturing, quality assurance and safety, scientists in research establishments, statutory authorities in the field of civil explosives, individual consultants to the explosive industry, managers in the mining industry, and so on. The contents of the book could be used to write up a production and safety manual as also for troubleshooting in existing operations. The blasting engineer may also be able to use its chapter on application to derive the maximum benefit from the use of the explosives.

The book, after exploring the evolution of these three types of explosives, will contain individual chapters dealing with science and technology, manufacturing, safety, and future R&D work needed.

Individual chapters are exclusive to the type of the explosive being discussed. The three major explosives dealt with are AN/FO, slurry/watergels, and emulsion explosives.

Individual chapters describe the following:

Classification/types/characteristics/definition

Explosives science

Raw materials and their role

Formulation techniques and components

Manufacturing technology

Quality – concept and assurance

Safety – understanding and practice

General topics of interest are contained in

future R&D work,

comparison with NG explosives,

comparison between ANFO, slurries, and emulsions,

economics of manufacture,

applications,

economics for the end user, and

references and bibliography.

Erode G. Mahadevan

Acknowledgment

It is not easy to write an acknowledgment for a book production as the number of people involved could be very many. The contents of my book are a mix of my own thinking and experience, but after stimulating discussions with various people connected with the global explosives industry and practical data collected over many years. But to my mind the motivation to stay and do research in this field was provided by the inspiring personality of Prof. T. Urbanskii with whom I came into contact while working in IDL industries, Hyderabad. The final impetus to write a book came through Dr. Martin Preuss of Wiley-VcH. I owe a lot to my family for their encouragement and support. Apart from these the various persons with whom I interacted in the industry at one time or the other inspired me to try and seek some answers to the phenomenon of explosives but special mention has to be made to the great working atmosphere provided by IDL Industries (now known as Gulf Oil India) where I spent a greater part of my career and gained hands-on knowledge in the field of explosives.

I am grateful to all the above for their role in motivating me to write a book primarily intended for the new entrants to the field of civil explosives as it stands today. Hopefully, I have succeeded in satisfying the readers of my book in whatever they expected from the contents.

I also wish to thank Dr. Martin Graf-Utzman and his staff for assisting me in finalizing this book.

Chapter 1

Classification of Explosives

Explosives are classified into different types and categories in various ways depending on their usage, sensitivity to initiation, and finished product packaging.

1.1 Initiation Sensitivity

Cap-sensitive explosives

: The explosive can be fully detonated with a measurable unconfined velocity in low diameters (1 inch) by initiating with a single detonator of No. 6 strength, which is the lowest strength detonator commercially made.

Booster-sensitive explosives (blasting agent)

: This type of explosive is detonated only when a booster of sufficient power is used to initiate it. These boosters are made of high explosives like pentaerythritol tetranitrate (PETN) and trinitro toluene (TNT) and are much more powerful than detonators (

Figure 1.1

).

Figure 1.1 Types of initiation.

Explosives are further classified into primary, secondary, and tertiary explosives depending on its level of sensitivity to external stimuli. Standardized testing evaluates the sensitivity in terms of friction, impact, heat, shock and based on these results, explosives are classified accordingly.

Nitroglycerine (NG) is very sensitive and classified as a primary explosive. TNT/RDX/dynamites are secondary explosives. These are relatively safe for handling and can be handled in large-scale production plants with acceptable degree of safety. Ammonium nitrate (AN) explosives are the least sensitive and come in the tertiary explosives group. Even though they may have higher detonation velocities and pressure than NG explosives, they are much safer to produce in very large quantities.

1.2 Size

Small diameter explosives

: These are usually explosives made in diameter of 7/8 to 2 in. and generally cap-sensitive.

Medium diameter explosives

: These are usually explosives made in diameters of 3–5 in. and are booster-sensitive only.

Large diameter explosives

: These are usually explosives made in diameter of 5–10 in. and are booster-sensitive only.

The boosters are in turn set off by either detonator or by a coil of detonating cord wound over and through it (see Figure 1.1).

1.3 Usage

The explosives are also classified into general purpose and permissible categories.

General-purpose explosives

: Usually in small diameter and cap-sensitive used for quarrying, tunneling, and cannot be used in underground coal mines.

Permissible explosives

: Cap-sensitive small-diameter explosives from 1 1/4 to 1 5/8 in. diameter, allowed by authorities for use in underground coal mines. Depending on the degree of gassiness (methane emission) found, there are further subclassifications. These differ from county to county depending on the test Procedures used.

1.4 Physical Form

Classification according to physical form of end product is as follows:

Cartridged explosive:

Here the explosive is in the form of cylindrical package, enclosed in paper or polythene tubings (flexible or rigid).

Pumpable explosives (bulk explosives):

Here the explosive is in the form of a flowy material and is capable of being pumped, augured, or poured. There is no outer packaging at all and the product is directly moved into the bore hole using bulk delivery trucks.

Any material which cannot be fully set off with a measurable velocity of detonation (VOD) either by detonator or by detonation is considered as “nonexplosive” in nature. However such nonexplosive material can be converted into an explosive by increasing its sensitivity.

Chapter 2

Explosive Science

2.1 Introduction

Explosives are known in practice as substances which work on the surroundings when they are set off. In the open area, their effectiveness is much less than under confinement because most of the work is done by expanding gases. Gas-producing event can be due to burning (deflagration) or explosion and detonation. One usually differentiates by the reaction velocities and pressures achieved in each of the phenomena. Thus while in deflagration, reaction velocities are much slower than velocity of sound and the pressures attained are in the range of bars. In detonation, the reaction velocity, which produces gas due to chemical reaction of the explosive with its own ingredients or air, exceeds the speed of sound in the material itself; thus there is a supersonic shock wave produced. The wavefront travels in advance of the release of expanding gases. The shock energy has a high peak pressure but is transient, whereas the gas energy is a longer lasting event though lower in peak pressure attained (see Figure 2.1) [1].

Figure 2.1 Schematic representations of zones and pressure variations along a detonating explosive charge.

2.1.1 Low Explosives

Deflagration and fast-burning substances which still perform some amount of work through release of gas are classified as low explosives. Black powder is a typical example. Reaction velocities are normally in the range of 600 − 1000 m/s (see Figure 2.2) [1].

Figure 2.2 Pressure profiles for low and high explosives.

2.1.2 High Explosives

Velocity of detonation (VOD) are in excess of 1800 m/s. Most commercial explosives and especially the ammonium nitrate (AN) based belong to the high explosives category due to their high detonation and gas pressures.